Haloadamantanes

ABSTRACT

HALOGENATED DERIVATIVES CONTAINING ADAMANTANE NUCLEUS ARE PRODUCED BY ADMIXING, IN THE PRESENCE OF STRONG SULFURIC ACID, ADAMANTANE OR ALKYL-SUBSTITUTED ADAMANTANT WITH A SELECTED HALO-YIELDING SALT OF AN ALKALI OR ALKALINE EARTH METAL, OR A CORRESPONDING HYDROGEN HALIDE.

"United States Patent M HALOADAMANTANES Robert E. Moore, Wilmington, Del., assignor to Sun Research and Development Co., Philadelphia, Pa. No Drawing. Original application Dec. 17, 1968, Ser. No.

784,486, now Patent No. 3,666,806. Divided and this application Sept. 20, 1971, Ser. No. 182,170

Int. Cl. C07c 17/00, 17/16 U.S. Cl. 260-648 R 10 Claims ABSTRACT OF THE DISCLOSURE Halogenated derivatives containing adamantane nucleus are produced by admixing, in the presence of strong sulfuric acid, adamantane or alkyl-substituted adamantane with a selected halo-yielding salt of an alkali or alkaline earth metal, or a corresponding hydrogen halide.

CROSS REFERENCE TO RELATED APPLICATION This application is a division of U.S. application Ser. No. 784,486, filed Dec. 17, 1968, now Pat. No. 3,666,806 by Robert E. Moore.

BACKGROUND OF THE INVENTION As shown, the bridgehead carbon atoms, customarily are designated by the numerals 1, 3, and 7 respectively.

The preparation of methyland/or ethyl-substituted adamantanes by the isomerization of tricyclic naphthenes by means of an aluminum halide or HF-BF catalyst has been described in several references including the following: Schneider U.S. Pat. No. 3,128,316, dated Apr. 7, 1964; Janoski and Moore U.S. Pat. No. 3,275,700, dated Sept. 27, 1966; Schleyer et al., Tetrahedron Letters No. 9, pp. 305-309 (1961); and Schneider et al., JACS, vol. 86, pp. 5365-5367 (1964). The isomerization products can have the methyl and/or ethyl groups attached to the adamantane nucleus at either bridgehead or non-bridgehead positions or both, although completion of the isomerization reaction favors bridgehead substitution. Examples of alkyladamantanes made by such isomerization are methyladamantanes, dimethyladamantanes, ethyladamantanes, methylethyladamantanes, 'dimethylethyladamantanes, trimethyladamantanes and tetramethyladamantanes.

Preparations of adamantane hydrocarbons having higher alkyl substituents have been described in the following references: Schneider U.S. Pat. No. 3,382,288, dated May 7, 1968; Spengler et al., Erdtil un Kohle- Erdgas-Petrochemie, vol. 15, pp. 702-707 (1962); and Hoek et al., 85 (1966), Recueil, 1045-1053.

3,784,615 Patented Jan. 8, 1974 SUMMARY OF THE INVENTION The invention resides in a process for producing halo compounds having any of the formulas: D-A-X; X-A--X; and X-AOH, wherein A represents a hydrocarbon moiety consisting of the adamantane nucleus with 0-3 alkyl substituents containing a total of not more than 20 alkyl carbon atoms; wherein not more than 2 such alkyl substituents of A occupy bridgehead positions on said nucleus; wherein X is a bridgehead substituent which is chloro, bromo or iodo; and wherein D is a bridgehead substituent which is hydrogen or alkyl, remaining substituents on A being hydrogen.

Said process is carried out by admixing, in the presence of sulfuric acid having a strength in the range of 96- 112% H equivalent by weight, and by preference, fuming sulfuric acid, a halogenating agent which is a chloride, bromide or iodide of lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, strontium, barium or hydrogen, with an adamantane hydrocarbon having the formula: D-AC wherein A represents the same hydrocarbon moiety as above; wherein C is a bridgehead substituent which is hydrogen; and wherein D is the same as defined above, i.e., hydrogen or alkyl having 1- 10 carbon atoms, remaining substituents on A being hydrogen; and thereafter recovering from the reaction mass one or more bridgehead halo products corresponding to the formulas: D--AX; X-AX; and XA-OH. In other words the reaction converts the starting adamantane hydrocarbon to a monohalo, a dihalo and/ or monohydroxymonohalo derivative thereof with these substituents being located at bridgehead positions on the adamantane nucleus.

For purposes of the present invention, adamantane hydrocarbons having one or more cycloalkyl groups on the nucleus are essentially equivalent as starting materials to corresponding adamantanes having non-cyclic saturated substituents of the same number of carbon atoms. Hence the term alkyl as used herein should be understood to include cycloalkyl.

DESCRIPTION Alkyl groups attached to the adamantane nucleus of the hydrocarbon reactant can be located at bridgehead or nonbridgehead positions. However, a maximum of three bridgehead positions on said nucleus can be occupied by alkyl groups leaving one bridgehead position open to be occupied by hydrogen for reaction in accordance with the invention, the product being a monohalo compound. In this particular situation, D is a bridgehead alkyl substituent, and moiety A per se (as defined) provides two alkyl groups occupying bridgehead positions on the adamantane nucleus with a possible third alkyl group occupying a nonbridgehead position.

Moiety A, as defined, being limited to two bridgehead alkyl substituents, when D is hydrogen, two bridgehead positions are made available for reaction in the production of l-halo, 1-halo-3-hydroxy and/0r 1,3-dihalo compounds in accordance with the invention.

1-ethyl-3,S-dimethyladamantane is an illustration of a compound with three alkyl substituents attached to the adamantane nucleus at bridgehead positions. In this instance, moiety A provides two such alkyl groups, and D the third.

1,3-dimethyladamantane is an illustration of an adamantane hydrocarbon with two bridgehead positions on the adamantane nucleus occupied by alkyl substituents, these being provided by moiety A, and D is hydrogen.

D is hydrogen in the case of monoalkyl substitution on the adamantane nucleus, and also in the case of adamantane itself.

Additional examples of starting material compounds in the practice of the invention are the following hydrocarbons: l-methyl or Z-methyladamantane; l-ethyl or 2- ethyladamantane; 1,2-, 1,3- or 1,4-dimethyladamantane; 1-ethyl-3-methyladamantane; diethyladamantanes; 1,3,5- trimethyladamantane; nonbridgehead trimethyladamantanes; l-n-propyl or l-isopropyladamantane; l-n-butyladamantane; 1,3-di-n-pentyladamantane; l-cyclopentyl or l-cyclohexyladamantane; l-methyl-3-hepty1adamantane; l-n-decyladamantane; l-n-decyl-3-ethyladamantane; 1,3- dicyclohexyladamantane; l-n-hexadecyladamantane; 1,3, -dicyclopentyladamantane; l-eicosyladamantane and the like. Other examples can be found in the references cited above.

Typical products are l-chloroadamantane; l-bromoadamantane, l-iodoadamantane; 1-chl0ro-3-hydroxyadamantane; 1,3-dichloroadamantane; l-bromo-3-hydroxyadamantane; 1,3-dibromoadamantane, 1-iodo-3-hydroxyadamantane; 1,3-diiodoadamantane; and corresponding alkyl-substituted adamantanes.

The invention is outstandingly advantageous when employing salts of the metals set forth above, for in such instance the reaction is very clean and the handling of corrosive and highly toxic elemental halogens, or, by choice, even their acids is avoided. Moreover, the process lends itself admirably to the use of a very lowcost source of halogen reactant, for example, common salt (NaCl).

0n the other hand, the acids of the halogens listed can be employed, with the handling inconvenience thus encountered balanced against halogen reactant cost, which not infrequently can be made quite low, such as when the halogen acid, e.g., HCl, is a by-product of some other reaction.

Moreover, insofar as the production of monohydroxymonohalo product is concerned, the invention provides a very convenient means for forming difunctional derivatives with two different functional substituents.

Preferably, the hydrocarbon moiety A in the hydrocarbon reactant has 0-10 total alkyl carbon atoms (in addition to the ten carbon atoms in the nucleus), with D being hydrogen. Also it is preferred that the hydrocarbon moiety A in the hydrocarbon reactant contain just two alkyl groups, each having 1 or 2 carbon atoms, and each occupying a bridgehead position, also with D being hydrogen.

The halogenated products resulting from the invention have a wide variety of uses. For example, monohalo products prepared according to the invention can be used as starting material for the preparation of methoxyalkyladamantanes as described in Moore US. Pat. No. 3,383,- 423, dated May 14, 1968. Dihalo products of the inven-, tion can be used to prepare 1,3-dicarboxyadamantanes in the manner disclosed in Moore US. Pat. No. 3,356,718, dated Dec. 5, 1967. The monohalomonohydroxy products, can be pryolyzed to produce S-methylene-l-ketobicyclo [3.3.1]nonane as such or in alkyl-substituted form, as described and claimed in Duling and Driscoll U.S. application Ser. No. 756,604, filed Aug. 30, 1968. In turn, the latter products find utility in the preparation of polyethers by treatment with acids in inert solvents to yield a thermally stable film-forming polymer useful for high temperature electrical insulation.

The products of the present invention are prepared from adamantane and alkyladamantanes. These compounds are reacted with hydrogen chloride, hydrogen bromide, hydrogen iodide, or by decided preference for the reasons set forth above, an alkali metal or alkaline earth metal salt thereof as set forth above, in the presence of strong sulfuric acid of strength in the range of 96- 112% H 50 equivalent, more preferably 99'l07% H 80 Upon diluting the resulting reaction mass with water, the desired halogenated compound or compounds can be recovered from the reaction mixture, e.g., by filtration or solvent extraction.

As an alternative procedure, the monohalo and dihalo products can be recovered from the reaction mass without dilution with water, by extraction from the reaction mixture by means of an inext solvent such as pentane or hexane, followed by evaporation of the solvent. Any hydroxyhalo product present in the mixture remains with the undiluted acid phase and is not extracted. If desired, the monohalo product can be separated from the dihalo product by distilling the monohalo material out of the extract.

The monohalo and dihalo products, and especially the latter, tend to have low solubility in the undiluted acid and hence often are recoverable at least in part from the reaction mixture by decantation and/or filtration without any usage of solvent. On the other hand, the monohalomonohydroxy products remain in the acid phase until it has been diluted with water.

The dihalo products generally are solids at room temperature while the monohalo products may be solid or liquid depending upon the particular adamantane hydrocarbon used as starting material. For example, the bridgehead monohalo anddihalo derivatives of 1,3-dimethyladamantane are, respectively, liquid and solid at room temperature; whereas for adamantane both the monohalo and dihalo bridgehead derivatives are normally solids. Hence the work-up procedure employed following the reaction may vary depending upon the nature of particular product compounds made.

The reaction is versatile from the standpoint of the production of desired primary products, the major prod-' uct in the reaction mass depending upon the molar ratio of halogenating reactant to adamantane hydrocarbon reactant and upon the strength of sulfuric acid employed.

To illustrate, assuming product recovery involves dilution with water, with lower acid concentrations, and with the above-mentioned molar ratio around 1: l, monohalo substitution is favored. However, as sulfuric acid concentration increases from the minimum of 96% and with about the same molar ratio, there is a tendency to produce more monohydroxymonohalo derivative upon aqueous dilution of the reaction mass. As the sulfuric acid strength approaches say 102% H equivalent by weight, production of the monohydroxymonohalo product becomes substantial, not infrequently, however, with the monohalo derivative still as the major product. With further increase in acid strength to the neighborhood of ICE-107% H 50 monohydroxymonohalo substitution tends to be maximized.

Reaction conditions become more and more favorable for the production of dihalo product as both acid concentration and molar ratio of halogenating reactant to adamantane hydrocarbon increase, 'with the result that as acid strength approaches and exceeds say 102% H SO equivalent by weight, and as the molar ratio exceeds 2:1, reaction conditions become more and more favorable for the production of dihalo product.

Mixtures of the three types of products, D--A--X, X-AX and XA0H, are frequently produced, which can be separated and worked up to obtain the individual products by procedures as indicated above.

Thus both acid strength and molar ratio play a part in product distribution in the reaction mass, leading to the following preferences.

In the production of monohalo product, an acid strength of 99-102% H 50 equivalent by weight along with a molar ratio of halogenating reactant to hydro carbon of 1:1 or thereabouts, and particularly somewhat in excess of 1:1 (e.g., a 10% excess) is preferred.

In the production of monohydroxymonohalo product, an acid strength of 102107% and particularly 102-105% H 80 equivalent by weight, along with a molar ratio of halogenating reactant to hydrocarbon of 1:1 or thereabouts is preferred.

In the production of dihalo product, an acid strength of 102-107% and particularly 102-105% H 80 equivalent by weight, along with a molar ratio of halogenating reactant to hydrocarbon in excess of 2:1 is preferred.

By way of example, 1,3-dimethyladamantane is reacted with a halo-yielding compound of the kind described above, each reactant initially by preference and for practical purposes in virtually anhydrous form, in the presence of fuming sulfuric acid (e.g., 100-105% H 80 equivalent), and the reaction product is then diluted with water. As brought out above, the product is primarily monohalo, monohalomonohydroxy or dihalo, depending upon the molar ratio of halo-yielding reactant to adamantane hydrocarbon reactant, and upon sulfuric acid strength. Not infrequently all three are present in amounts making recovery of each commercially feasible.

In elfecting the reaction, the sulfuric acid should have a high enough acid strength and be used in large enough amount for the desired reaction to take place. Generally speaking, lower acid strengths, and lesser amounts thereof, other things being the same, favor monohalo substitution. In all cases the strength of the starting acid should be of at least 96% H SO equivalent by weight, and it is distinctly preferable to employ fuming sulfuric acid. An H 80 equivalent in the range of 96112% can be employed, the range of 100-105% being quite useful. And while any desired volume ratio of sulfuric acid to hydrocarbon can be employed, a volume ratio in the range of 1:1 to :1 is quite satisfactory, with the range of 3:1 to 10:1 being preferred.

For making either the monohalo or monohydroxymonohalo product, it is desirable first to mix all of the starting hydrocarbon with the sulfuric acid and thereafter add the halogenating reactant slowly while mixing until the molar ratio thereof to the hydrocarbon reaches 1:1 or slightly in excess of this proportion. When the adamantane hydrocarbon and the acid are first admixed, a twophase dispersion or emulsion is formed since the hydrocarbon itself has a relatively low solubility in the acid. However the hydrocarbon material becomes solubilized in the acid as mixing is continued, probably due to its conversion to a carbonium ion form, and this conversion will cause all of it to go into solution if sufiicient mixing time is allowed. Mixing of the admixture is carried out until at least a substantial proportion of the adamantane hydrocarbon has dissolved in the acid or until substantially all of it has dissolved, following which the halogenating reagent is added while continuing the mixing. After all of the halogenating reagent has reacted, the reaction mass can be worked up as previously described to recover the products.

When the dihalo derivative is the desired product, it is preferable to add both the adamantane hydrocarbon and the halogenating reagent to the fuming acid continuously or intermittently while mixing, employing a molar ratio of halogenating compound to hydrocarbon of about 2:1. This procedure favors the formation of X-AX which product largely precipitates as a solid from the reaction mixture as it is formed.

Temperature conditions maintained during the reaction follow the well-known rule, namely, other conditions remaining the same, they should be sufiiciently high for the reaction to take place, preferably at a reasonable rate, and not so high as to result largely in unwanted products, such as decomposition products, and preferably not significantly in such products. Higher temperatures are permissible, and may be required for a reasonable rate of reaction, when employing lower sulfuric acid strengths, e.g., 9699% H 80 whereas reduced temperatures are recommended when employing relatively high sulfuric acid strengths. Thus, for example and generally speaking, the reaction can be carried out under temperature conditions virtually between the freezing point of the acid (circa 8-10 C.) and say 75 C., but it is generally preferable to maintain temperature conditions in the range of 10-30" C. A good practical operating rule is to reduce reaction temperature conditions with increase in sulfuric acid strength.

After the first phase of the process has been completed, the reaction mass can be diluted with water to initiate the second phase, i.e., separation of the desired products. This is conveniently accomplished by pouring the strongly acidic mass over cracked ice or into ice water to effect dilution while simultaneously preventing the temperature from rising an inordinate amount. Enough water (e.g., ice) ought to be used to adequately decrease the strength of the sulfuric acid so that the desired dilution will proceed to conclusion. Generally, the strength of the acid ought to be brought down to less than 60% H 50 by Weight and, if desired, to considerably less than this level (e.g., below 20% H 80 When the acid is sufficiently diluted all reaction products become insoluble and will precipitate. The product or products can be separated from the reaction mass by any suitable means, such as filtration and/ or decantation.

On the other hand, in recovering the monohalo and dihalo products, the step of dilution with water can be omitted, and such product or products can be separated from the reaction mass by solvent extraction as previously described.

Example 10 g. of 1,3-dimethyladamantane (for convenience, DMA) were added without stirring to 100 cc. of 20% oleum (104.5% H 50 equivalent by weight) maintained at a temperature of about 10 C. The mixture was stirred vigorously for 5 minutes, by which time almost all of the DMA had gone into solution. Sodium chloride in amount of 7.5 g., providing a molar ratio with respect to hydrocarbon of 2:1, was then added slowly to the reaction mass with stirring over a period of 15 minutes. This was followed by dilution with ice. Upon melting of the ice the mass was filtered to remove a crude solid which upon analysis by VPC showed the following composition:

The reaction exemplified by the preceding example is quite versatile from the standpoint of product yield. To illustrate, if a higher yield of the monohydroxymonohalo product is desired, the molar ratio of halo-yielding compound to hydrocarbon can be reduced, for example, down to 1:1 or lower; or, if a higher yield of the monohalo product is desired, the molar ratio of halo-yielding compound to hydrocarbon likewise can be reduced to 1:1, accompanied by a reduction in acid strength to say 100% H 50 to reduce formation of monohydroxymonohalo product. On the other hand, if it is desired to maximize the dihalo product, the procedure should be varied to add both reagents to the acid in small increments, keeping said molar ratio preferably higher than 2:1.

Substantially analogous results are obtained when other compounds having the adamantane nucleus and the formula DAC as above defined are substituted as starting material in the above example, and the same applies to the substitution in said example of other halo-yielding metal salts of the character set forth herein as well as the halogen halides.

The invention claimed is:

1. Process for producing compounds having the adamantane nucleus which comprises admixing, in the presence of sulfuric acid having a strength in the range of 96112% H equivalent by weight and at a temperature between the freezing point of the acid and 75 C., a halogenating reactant which is a chloride of hydrogen or a metal selected from the group consisting of lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, strontium and barium, with an adamantane hydrocarbon having the formula: DAC wherein A represents a hydrocarbon moiety consisting of the adamantane nucleus with -3 alkyl or cycloalkyl substituents containing a total of not more than 20 alkyl or cycloalkyl carbon atoms; wherein not more than two such alkyl or cycloalkyl substituents of A occupy bridgehead positions on said nucleus; wherein C and D are bridgehead substituents which are hydrogen; the remaining substituents on A being hydrogen; and thereafter recovering from the reaction mass a compound of the formula: XA-X wherein X represents a bridgehead chloride.

2. Process of claim 1 wherein the sulfuric acid strength falls in the range of 99-107% H 80 equivalent by weight.

3. Process of claim 2 wherein said temperature is in the range of 10-30 C.

4. Process of claim 2 wherein the halogenating reactant is a metal chloride.

5. Process of claim 4 wherein the halogenating reactant is sodium chloride.

6. Process of claim 4 wherein said temperature is in the range of 1030 C.

7. Process of claim 2 wherein the sulfuric acid strength is 102-107% H 80 equivalent by weight, and the molar ratio of halogenating reactant is in excess of 2:1.

8. Process of claim 2 wherein moiety A contains two alkyl substituents each occupying a bridgehead position,

said two substituents containing a total of not more than 10 carbon atoms.

9. Process of claim 8 wherein each alkyl substituent in moiety A contains one or two carbon atoms.

10. Process of claim 9 wherein the halogenating reactant is sodium chloride.

References Cited UNITED STATES PATENTS 3,283,001 12/1964 Brown 260648 R 3,666,806 5/1972 Moore 260617 F FOREIGN PATENTS 1,101,410 3/1961 Germany 260648 R OTHER REFERENCES Geluk et al., Tetrahedron, vol. 24, pp. 5361-5377, 1968.

Stepanov et al., J. Org. Chem., USSR 2, p. 1609-1610. 1966.

Ephraim, Inorganic Chemistry, Interscience Publishers, New York, pp. 239-240, 1955.

Mellor, Modern Inorganic Chemistry, Longmans Green & Co., New York, pp. 523, 525, 502, 503 (1954).

Olan, Friedel Crafts and Related Reactions, Interscience Publishers, New York, p. 26, 1963.

HOWARD T. MARS, Primary Examiner 

